Piercing-mandrel.



R. J. GARDINER.

PIERG NNNNNNN REL.

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945,932 Patented Jan. 11,1910.

ROBERT JAMES GARDINER, OF TINSLEY, NEAR SI-IEFFIELD, ENGLAND, ASSIGNORTO STEWARTS 6L LLOYDS LIMITED, OF BIRMINGHAM, ENGLAND.

PIERCING-MANDREL.

Specification of L etters Patent.

Patented J an. 11, 1910.

Application filed February 9, 1909. Serial No. 476,876.

To all whom it may concern:

Be it known that I, ROBERT J AMEs GARDI- NER, subject of Great Britain,residing at 9 Sheffield road, Tinsley, near Sheiiield, Eng land, haveinvented new and useful Improvements in Piercing-Mandrels, of which thefollowing is a specification.

This invention relates to the production of steel or other metal tubesand has for its object to provide an improved mandrel for use moreespecially in the piercing operation of weldless tube manufacture.Previously such a mandrel has comprised a bar fitted at its operativeend with a detachable bulb or enlargement made of chilled cast iron. Toincrease the durability of the bulb it has been proposed to provide ahard steel nose or point forming part of a steel core having the bodypart of the bulb cast thereon.

he present invention comprises the formation of the cast iron portion ofthe bulb on or around the end of the mandrel bar as hereinafterdescribed, and the provision within a central socket formed in the bulband extending if required into the bar, of a steel or equivalent nosepiece or point.

Referring to the accompanying sheet of explanatory drawings ,#Figures 1and 2 are respectively sectional diagrams illustrating two ways ofcarrying the invention into effect. Y

The same reference letters in the two views indicate the same or similarparts.

In the application of the invention as shown at Fig. l the end of theordinary mild steel bar a is provided near its forward eX- tremity withan annular enlargement or collar Z) and around such end is cast in anyconvenient manner the body part of the bulb c. At the point of the bulba central tapered socket is left for the reception of a suitable steelnose or point al. Coaxially with the socket in the bulb a socket or holemay be formed in the end of the mandrel bar for the reception of thestem or rear extremity or elongation e of the steel nose. Preferably thenose is placed in position first and the bulb cast around the same andthe bar, leaving the point of the nose exposed. Fig. 2 shows a mandrelwith a groove b around its end portion instead of a collar as aforesaid.

A mandrel having its operative end constructed as herein described ismore convenient in service than one having a detachable bulb on accountof the rigid connection provided between the bulb and stem. For renewalthe case iron portion is broken away and replaced by the casting ofanother on the 1 bar, and the steel point may also be withdrawn whenrequired. Security of the connection between the bulb and bar is insuredby the collars or recesses above referred to.

Having thus described my invention, what I claim and desire to secure byLetters Patent is l. In piercing mandrels for use in the manufacture ofweldless steel or other metal tubes, the combination with a mandrel bar,of a bulb cast on one end of the bar, means vformed with the bar forinsuring the security of the bulb, a socket formed in the bulb, and asteel nose secured in the socket, substantially as described.

2. In piercing mandrels for use in the manufacture of weldless steel orother metal tubes, the combination with a mandrel bar, of a collarformed near one end of the bar, a bulb cast over the said end andcollar, a socket formed in the bulb, and a steel nose secured in thesocket, substantially as described.

3. In piercing mandrels for use in the manufact-ure of weldless steel orother metal tubes, the combination with a mandrel bar, of a bulb cast onone end of the bar, means formed with the bar for insuring the securityof the bulb, coaxial sockets formed in the bulb and bar, and a steelnose secured in said sockets, substantially as described.

4. In piercing mandrels for use in the manufacture of weldless steel orother metal tubes, the combination with a mandrel bar of a collar formednear one end of the bar, a socket in the said end of the bar, a steelnose inserted in said socket, and a bulb cast around the bar end, collarand steel nose, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

ROBERT JAMES GARDINER.

Witnesses:

JOHN MORGAN,

HARRY DAVIS.

